Problem 1: Home work Muscat Corporation purchased a new machine for its assembly process on August 1, 2010. The cost of this machine was $150,000. The company estimated that the machine would have a salvage value of $24,000 at the end of its service life. Its life is estimated at 5 years and its working hours are estimated at 21,000 hours. Year-end is December 31. Instructions: Compute the depreciation expense under the following methods. (a) Straight-line depreciation. (c) Sum-of-the-years'-digits. (b) Activity method (d) Double-declining balance